Infrared imaging systems operating in the 3-5 .mu.m and 8-12 .mu.m spectral regions are required for many electro-optical systems in order to provide coverage for day/night and/or bad weather operation. In recent years, considerable effort has been devoted to the development of InSb and HgCdTe infrared imaging devices. For the 3-5 .mu.m spectral region, an InSb charge injection device (CID) offers significant potential for the realization of cost-effective infrared staring imaging systems because of the relative simplicity in structure, fabrication and operation of CID arrays. Such systems have been described previously by M. Gibbons and S. Wang, "Status of CID InSb Detector Technology", Proc. SPIE Int. Soc. Opt. Eng., Vol. 443, 151 (1984) and, Ali Bahraman and David N. Pocock, "Monolithic 128.times.128 InSb FPAs for Staring Infrared Systems," IEDM Digest, 726 (December 1983). These prior art disclosures have presented performance data and thermal imagery obtained from 128.times.128 staring focal plane arrays. In an exemplary prior art design of which the present invention is an improvement there were 6 layers of material and 5 masking steps, one of which was critical and selectively removed an aluminum layer from a Cr layer until the latter was 50 Angstroms to 70 Angstroms thick. This masking step patterned the removed portions so that the 50 Angstroms-70 Angstroms Cr metal layer remaining formed an optical window to each element of the device. The criticality of this step gave poor product yield, limiting the sensitivity of the device and increasing its internal capacitance.